svn commit: r316676 - in head/sys/netinet: . tcp_stacks
Julian Elischer
julian at freebsd.org
Mon Apr 10 14:51:42 UTC 2017
If possible MFC to 10 too would be nice..
thanks
On 10/4/17 4:19 pm, Steven Hartland wrote:
> Author: smh
> Date: Mon Apr 10 08:19:35 2017
> New Revision: 316676
> URL: https://svnweb.freebsd.org/changeset/base/316676
>
> Log:
> Use estimated RTT for receive buffer auto resizing instead of timestamps
>
> Switched from using timestamps to RTT estimates when performing TCP receive
> buffer auto resizing, as not all hosts support / enable TCP timestamps.
>
> Disabled reset of receive buffer auto scaling when not in bulk receive mode,
> which gives an extra 20% performance increase.
>
> Also extracted auto resizing to a common method shared between standard and
> fastpath modules.
>
> With this AWS S3 downloads at ~17ms latency on a 1Gbps connection jump from
> ~3MB/s to ~100MB/s using the default settings.
>
> Reviewed by: lstewart, gnn
> MFC after: 2 weeks
> Relnotes: Yes
> Sponsored by: Multiplay
> Differential Revision: https://reviews.freebsd.org/D9668
>
> Modified:
> head/sys/netinet/in_kdtrace.c
> head/sys/netinet/in_kdtrace.h
> head/sys/netinet/tcp_input.c
> head/sys/netinet/tcp_output.c
> head/sys/netinet/tcp_stacks/fastpath.c
> head/sys/netinet/tcp_var.h
>
> Modified: head/sys/netinet/in_kdtrace.c
> ==============================================================================
> --- head/sys/netinet/in_kdtrace.c Mon Apr 10 06:19:09 2017 (r316675)
> +++ head/sys/netinet/in_kdtrace.c Mon Apr 10 08:19:35 2017 (r316676)
> @@ -132,6 +132,14 @@ SDT_PROBE_DEFINE6_XLATE(tcp, , , state__
> "void *", "void *",
> "int", "tcplsinfo_t *");
>
> +SDT_PROBE_DEFINE6_XLATE(tcp, , , receive__autoresize,
> + "void *", "void *",
> + "struct tcpcb *", "csinfo_t *",
> + "struct mbuf *", "ipinfo_t *",
> + "struct tcpcb *", "tcpsinfo_t *" ,
> + "struct tcphdr *", "tcpinfoh_t *",
> + "int", "int");
> +
> SDT_PROBE_DEFINE5_XLATE(udp, , , receive,
> "void *", "pktinfo_t *",
> "struct inpcb *", "csinfo_t *",
>
> Modified: head/sys/netinet/in_kdtrace.h
> ==============================================================================
> --- head/sys/netinet/in_kdtrace.h Mon Apr 10 06:19:09 2017 (r316675)
> +++ head/sys/netinet/in_kdtrace.h Mon Apr 10 08:19:35 2017 (r316676)
> @@ -65,6 +65,7 @@ SDT_PROBE_DECLARE(tcp, , , debug__input)
> SDT_PROBE_DECLARE(tcp, , , debug__output);
> SDT_PROBE_DECLARE(tcp, , , debug__user);
> SDT_PROBE_DECLARE(tcp, , , debug__drop);
> +SDT_PROBE_DECLARE(tcp, , , receive__autoresize);
>
> SDT_PROBE_DECLARE(udp, , , receive);
> SDT_PROBE_DECLARE(udp, , , send);
>
> Modified: head/sys/netinet/tcp_input.c
> ==============================================================================
> --- head/sys/netinet/tcp_input.c Mon Apr 10 06:19:09 2017 (r316675)
> +++ head/sys/netinet/tcp_input.c Mon Apr 10 08:19:35 2017 (r316676)
> @@ -1486,6 +1486,68 @@ drop:
> return (IPPROTO_DONE);
> }
>
> +/*
> + * Automatic sizing of receive socket buffer. Often the send
> + * buffer size is not optimally adjusted to the actual network
> + * conditions at hand (delay bandwidth product). Setting the
> + * buffer size too small limits throughput on links with high
> + * bandwidth and high delay (eg. trans-continental/oceanic links).
> + *
> + * On the receive side the socket buffer memory is only rarely
> + * used to any significant extent. This allows us to be much
> + * more aggressive in scaling the receive socket buffer. For
> + * the case that the buffer space is actually used to a large
> + * extent and we run out of kernel memory we can simply drop
> + * the new segments; TCP on the sender will just retransmit it
> + * later. Setting the buffer size too big may only consume too
> + * much kernel memory if the application doesn't read() from
> + * the socket or packet loss or reordering makes use of the
> + * reassembly queue.
> + *
> + * The criteria to step up the receive buffer one notch are:
> + * 1. Application has not set receive buffer size with
> + * SO_RCVBUF. Setting SO_RCVBUF clears SB_AUTOSIZE.
> + * 2. the number of bytes received during the time it takes
> + * one timestamp to be reflected back to us (the RTT);
> + * 3. received bytes per RTT is within seven eighth of the
> + * current socket buffer size;
> + * 4. receive buffer size has not hit maximal automatic size;
> + *
> + * This algorithm does one step per RTT at most and only if
> + * we receive a bulk stream w/o packet losses or reorderings.
> + * Shrinking the buffer during idle times is not necessary as
> + * it doesn't consume any memory when idle.
> + *
> + * TODO: Only step up if the application is actually serving
> + * the buffer to better manage the socket buffer resources.
> + */
> +int
> +tcp_autorcvbuf(struct mbuf *m, struct tcphdr *th, struct socket *so,
> + struct tcpcb *tp, int tlen)
> +{
> + int newsize = 0;
> +
> + if (V_tcp_do_autorcvbuf && (so->so_rcv.sb_flags & SB_AUTOSIZE) &&
> + tp->t_srtt != 0 && tp->rfbuf_ts != 0 &&
> + TCP_TS_TO_TICKS(tcp_ts_getticks() - tp->rfbuf_ts) >
> + (tp->t_srtt >> TCP_RTT_SHIFT)) {
> + if (tp->rfbuf_cnt > (so->so_rcv.sb_hiwat / 8 * 7) &&
> + so->so_rcv.sb_hiwat < V_tcp_autorcvbuf_max) {
> + newsize = min(so->so_rcv.sb_hiwat +
> + V_tcp_autorcvbuf_inc, V_tcp_autorcvbuf_max);
> + }
> + TCP_PROBE6(receive__autoresize, NULL, tp, m, tp, th, newsize);
> +
> + /* Start over with next RTT. */
> + tp->rfbuf_ts = 0;
> + tp->rfbuf_cnt = 0;
> + } else {
> + tp->rfbuf_cnt += tlen; /* add up */
> + }
> +
> + return (newsize);
> +}
> +
> void
> tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
> struct tcpcb *tp, int drop_hdrlen, int tlen, uint8_t iptos,
> @@ -1849,62 +1911,7 @@ tcp_do_segment(struct mbuf *m, struct tc
> #endif
> TCP_PROBE3(debug__input, tp, th, m);
>
> - /*
> - * Automatic sizing of receive socket buffer. Often the send
> - * buffer size is not optimally adjusted to the actual network
> - * conditions at hand (delay bandwidth product). Setting the
> - * buffer size too small limits throughput on links with high
> - * bandwidth and high delay (eg. trans-continental/oceanic links).
> - *
> - * On the receive side the socket buffer memory is only rarely
> - * used to any significant extent. This allows us to be much
> - * more aggressive in scaling the receive socket buffer. For
> - * the case that the buffer space is actually used to a large
> - * extent and we run out of kernel memory we can simply drop
> - * the new segments; TCP on the sender will just retransmit it
> - * later. Setting the buffer size too big may only consume too
> - * much kernel memory if the application doesn't read() from
> - * the socket or packet loss or reordering makes use of the
> - * reassembly queue.
> - *
> - * The criteria to step up the receive buffer one notch are:
> - * 1. Application has not set receive buffer size with
> - * SO_RCVBUF. Setting SO_RCVBUF clears SB_AUTOSIZE.
> - * 2. the number of bytes received during the time it takes
> - * one timestamp to be reflected back to us (the RTT);
> - * 3. received bytes per RTT is within seven eighth of the
> - * current socket buffer size;
> - * 4. receive buffer size has not hit maximal automatic size;
> - *
> - * This algorithm does one step per RTT at most and only if
> - * we receive a bulk stream w/o packet losses or reorderings.
> - * Shrinking the buffer during idle times is not necessary as
> - * it doesn't consume any memory when idle.
> - *
> - * TODO: Only step up if the application is actually serving
> - * the buffer to better manage the socket buffer resources.
> - */
> - if (V_tcp_do_autorcvbuf &&
> - (to.to_flags & TOF_TS) &&
> - to.to_tsecr &&
> - (so->so_rcv.sb_flags & SB_AUTOSIZE)) {
> - if (TSTMP_GT(to.to_tsecr, tp->rfbuf_ts) &&
> - to.to_tsecr - tp->rfbuf_ts < hz) {
> - if (tp->rfbuf_cnt >
> - (so->so_rcv.sb_hiwat / 8 * 7) &&
> - so->so_rcv.sb_hiwat <
> - V_tcp_autorcvbuf_max) {
> - newsize =
> - min(so->so_rcv.sb_hiwat +
> - V_tcp_autorcvbuf_inc,
> - V_tcp_autorcvbuf_max);
> - }
> - /* Start over with next RTT. */
> - tp->rfbuf_ts = 0;
> - tp->rfbuf_cnt = 0;
> - } else
> - tp->rfbuf_cnt += tlen; /* add up */
> - }
> + newsize = tcp_autorcvbuf(m, th, so, tp, tlen);
>
> /* Add data to socket buffer. */
> SOCKBUF_LOCK(&so->so_rcv);
> @@ -1945,10 +1952,6 @@ tcp_do_segment(struct mbuf *m, struct tc
> win = 0;
> tp->rcv_wnd = imax(win, (int)(tp->rcv_adv - tp->rcv_nxt));
>
> - /* Reset receive buffer auto scaling when not in bulk receive mode. */
> - tp->rfbuf_ts = 0;
> - tp->rfbuf_cnt = 0;
> -
> switch (tp->t_state) {
>
> /*
>
> Modified: head/sys/netinet/tcp_output.c
> ==============================================================================
> --- head/sys/netinet/tcp_output.c Mon Apr 10 06:19:09 2017 (r316675)
> +++ head/sys/netinet/tcp_output.c Mon Apr 10 08:19:35 2017 (r316676)
> @@ -831,11 +831,13 @@ send:
> to.to_tsval = tcp_ts_getticks() + tp->ts_offset;
> to.to_tsecr = tp->ts_recent;
> to.to_flags |= TOF_TS;
> - /* Set receive buffer autosizing timestamp. */
> - if (tp->rfbuf_ts == 0 &&
> - (so->so_rcv.sb_flags & SB_AUTOSIZE))
> - tp->rfbuf_ts = tcp_ts_getticks();
> }
> +
> + /* Set receive buffer autosizing timestamp. */
> + if (tp->rfbuf_ts == 0 &&
> + (so->so_rcv.sb_flags & SB_AUTOSIZE))
> + tp->rfbuf_ts = tcp_ts_getticks();
> +
> /* Selective ACK's. */
> if (tp->t_flags & TF_SACK_PERMIT) {
> if (flags & TH_SYN)
>
> Modified: head/sys/netinet/tcp_stacks/fastpath.c
> ==============================================================================
> --- head/sys/netinet/tcp_stacks/fastpath.c Mon Apr 10 06:19:09 2017 (r316675)
> +++ head/sys/netinet/tcp_stacks/fastpath.c Mon Apr 10 08:19:35 2017 (r316676)
> @@ -399,62 +399,8 @@ tcp_do_fastnewdata(struct mbuf *m, struc
> (void *)tcp_saveipgen, &tcp_savetcp, 0);
> #endif
> TCP_PROBE3(debug__input, tp, th, m);
> - /*
> - * Automatic sizing of receive socket buffer. Often the send
> - * buffer size is not optimally adjusted to the actual network
> - * conditions at hand (delay bandwidth product). Setting the
> - * buffer size too small limits throughput on links with high
> - * bandwidth and high delay (eg. trans-continental/oceanic links).
> - *
> - * On the receive side the socket buffer memory is only rarely
> - * used to any significant extent. This allows us to be much
> - * more aggressive in scaling the receive socket buffer. For
> - * the case that the buffer space is actually used to a large
> - * extent and we run out of kernel memory we can simply drop
> - * the new segments; TCP on the sender will just retransmit it
> - * later. Setting the buffer size too big may only consume too
> - * much kernel memory if the application doesn't read() from
> - * the socket or packet loss or reordering makes use of the
> - * reassembly queue.
> - *
> - * The criteria to step up the receive buffer one notch are:
> - * 1. Application has not set receive buffer size with
> - * SO_RCVBUF. Setting SO_RCVBUF clears SB_AUTOSIZE.
> - * 2. the number of bytes received during the time it takes
> - * one timestamp to be reflected back to us (the RTT);
> - * 3. received bytes per RTT is within seven eighth of the
> - * current socket buffer size;
> - * 4. receive buffer size has not hit maximal automatic size;
> - *
> - * This algorithm does one step per RTT at most and only if
> - * we receive a bulk stream w/o packet losses or reorderings.
> - * Shrinking the buffer during idle times is not necessary as
> - * it doesn't consume any memory when idle.
> - *
> - * TODO: Only step up if the application is actually serving
> - * the buffer to better manage the socket buffer resources.
> - */
> - if (V_tcp_do_autorcvbuf &&
> - (to->to_flags & TOF_TS) &&
> - to->to_tsecr &&
> - (so->so_rcv.sb_flags & SB_AUTOSIZE)) {
> - if (TSTMP_GT(to->to_tsecr, tp->rfbuf_ts) &&
> - to->to_tsecr - tp->rfbuf_ts < hz) {
> - if (tp->rfbuf_cnt >
> - (so->so_rcv.sb_hiwat / 8 * 7) &&
> - so->so_rcv.sb_hiwat <
> - V_tcp_autorcvbuf_max) {
> - newsize =
> - min(so->so_rcv.sb_hiwat +
> - V_tcp_autorcvbuf_inc,
> - V_tcp_autorcvbuf_max);
> - }
> - /* Start over with next RTT. */
> - tp->rfbuf_ts = 0;
> - tp->rfbuf_cnt = 0;
> - } else
> - tp->rfbuf_cnt += tlen; /* add up */
> - }
> +
> + newsize = tcp_autorcvbuf(m, th, so, tp, tlen);
>
> /* Add data to socket buffer. */
> SOCKBUF_LOCK(&so->so_rcv);
> @@ -532,10 +478,6 @@ tcp_do_slowpath(struct mbuf *m, struct t
> win = 0;
> tp->rcv_wnd = imax(win, (int)(tp->rcv_adv - tp->rcv_nxt));
>
> - /* Reset receive buffer auto scaling when not in bulk receive mode. */
> - tp->rfbuf_ts = 0;
> - tp->rfbuf_cnt = 0;
> -
> switch (tp->t_state) {
>
> /*
>
> Modified: head/sys/netinet/tcp_var.h
> ==============================================================================
> --- head/sys/netinet/tcp_var.h Mon Apr 10 06:19:09 2017 (r316675)
> +++ head/sys/netinet/tcp_var.h Mon Apr 10 08:19:35 2017 (r316676)
> @@ -778,6 +778,8 @@ void hhook_run_tcp_est_in(struct tcpcb *
> #endif
>
> int tcp_input(struct mbuf **, int *, int);
> +int tcp_autorcvbuf(struct mbuf *, struct tcphdr *, struct socket *,
> + struct tcpcb *, int);
> void tcp_do_segment(struct mbuf *, struct tcphdr *,
> struct socket *, struct tcpcb *, int, int, uint8_t,
> int);
>
>
More information about the svn-src-head
mailing list